There exist numerous applications from the applicant which relate to longitudinal register control in processing machines, in which the processing devices are implemented as clamping points and there is therefore coupling between longitudinal register and web tensile force. In this case, a correction to the processing position always also leads to a change in speed of the product web and therefore to a change in the tensile force and vice versa.
However, no solutions exist for the non-contact case forming the basis here, in which in particular no speed change occurs as a result of longitudinal register control. However, a change in speed occurs in the event of a change in the web tensile force without the processing position being changed at the same time. The known methods for avoiding longitudinal register errors cannot be applied here.
It is therefore desirable to specify a method with which a register deviation as a result of a tensile force change can be kept as low as possible or eliminated.